The calpain system has been detected in every vertebrate tissue examined, and has been suggested to play a regulatory role in cellular protein metabolism. This regulatory role may have important implications in platelet aggregation and pathologies associated with altered calcium homeostasis and protein metabolism such as ischemic cell injury and degenerative diseases. Inhibitors of calpain have been shown to block dexamethasone and low-level irradiation induced apoptosis in thymocytes suggesting that calpain has a regulatory or mechanistic role in apoptotic cell death.Calpastatin, a specific endogenous inhibitor of calpain, has a predicted molecular weight of ~77kD and an internal repeat of four homologous domains which allow it to inhibit multiple calpain molecules simultaneously. It functions by binding to calpain when calpain binds calcium. When Calpastatin is subjected to proteolytic digestion, fragments of calpastatin as small as 15kD still retain inhibitory activity.
Cellular Localization: Cytoplasmic and Nuclear
Applications:
Suitable for use in Western Blot and Immunocytochemistry. Other applications not tested.
Recommended Dilution:
Optimal dilutions to be determined by the researcher.
Storage and Stability:
May be stored at 4 degrees C for short-term only. For long-term storage and to avoid repeated freezing and thawing, aliquot Store at -20 degrees C. Aliquots are stable for at least 12 months at -20 degrees C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.